Heat exchange system control



Aug. 29, 1933. L. F. wHnNEY 1,924, 95

HEAT EXCHANGE SYSTEM CONTROL Filed Jan. 30, 1931 2 Sheets-Sheet lInventor Lyman 1? Whitney. 777 Att yS.

Aug. 29, 1933. F WHITNEY 1,924,895

H EAT EXCHANGE SYSTEM CONTROL Filed Jan. 30, 1931 2 Sheets-Sheet 2.

66 I f 37/ 74 Aj? 6/ 58 A a 74 w 5/ I 5.5

W 70 Inventor Att ys.

Patented Aug. 29, 1933 UNITED STATES HEAT. EXCHANGE SYSTEM CONTROL 11Claim.

This invention relates to a control arrangement for boilers and/or heatexchange systems such as refrigerating systems and in one aspect relatesto means arranged to impede or stop the heating of a boiler! when aninsumcient amount of liquid is supplied tothe same or the liquid in theboiler is depleted for any reason.

This invention affords a safety arrangement for a refrigerating systemwhich employs a boiler and which may include means for maintaining a lowsubatmospheric pressure in the system. In accordance with the presentinvention, the system may be so arranged that an increase in theinternal pressure thereof, due, for example, to the leakage of air intothe system or to the failure of the purger to operate. will be effectivein causing the; depletion of the liquid in the boiler and consequentinterruption to the supply of heat to the boiler, while the heating ofthe' boiler will also be interrupted should the liquid level thereinbecome unduly low for any other reason. The present invention providesan arrangement which is particularly adapted to employment in systemshaving a pipe or duct connected to the boiler and normally containingliquid as, for example, liquid that is being fed to the boiler. Thus theinvention may be employed in refrigerating systems having vaporizers orboilers, the liquid in which is being replenished by means of a ductwhich may contain a column of the fluid to be vaporized. For example,this invention is particularly advantageous when employed with arefrigerating system of the character disclosed in the Patent No.1,761,551 to Eastman A. Weaver dated June 3, 1930 and the copendingapplica tion of Daniel F. Comstock, No. 198,715, filed June 11,192! aswell as my copending application, Serial No. 503,006 filed December1'7,- 1930. The above identified patent and applications discloserefrigerating apparatus which includes a boiler or vaporizer for thepropellent fluid, which preferably may be mercury, and the vapor-ofwhich is supplied to the aspirator nozzle for entrainment of refrigerantvapor from a cooler, the propellant being condensed after theentrainment of the refrigerant and a pressure balancing column to theboiler.

In accordance with the present invention,ya suitable control factor maybe provided to interrupt the application of heat to the boiler when theliquid level in the latter becomes inordinately low. Such a controlfactor preferably is associated with the duct which feeds liquid to theboiler, and it may include a thermostatic element which is actuated whenthe liquid contained returned through 7 Application January 30, 1931.Serial N0. 512,405

within the duct is displaced ordinarily has a much higher PATENT oar-iceby the vapor, which temperature than the liquid in this part of thesystem,

and has a much greater heat supplying power. 1

Thus, in the case of a boiler gas burner,

pro ded with a a thermostatic control member may normally serve toretain'a valve in the fuel sup-. ply line in-its open position, whilg anincrease in the temperature of the may be eifective thus interruptingthe flow of in causing the valve to close, fuel to the burner.

A further aspect of the invention relates to the arrangement of a lowpressure system such as a refrigerating system which is provided withthermostatic member means that interrupt the normal flow of liquid tothe boiler should the pressurewithin the system rise due to the leakageof atmospheric air or for any other reason. The systemthat such anincrease in pressure in the boiler, where.-

lowering of the liquid level is arranged so will result in upon thecontrol device operates to interrupt the supply 'of heat to the boilerand operatioribfthe system.

- In the accompanying drawings:

Fig. 1 is a schematic view of are! thus stop future system to which mysafety controlarrangement is applied;

Fig. 2 is an enlarged horizontal section through, and the associatedliquid the control member duct;

Fig. 3 is Fig. 2;

Fig. 4 is a top view of the control means, ing the fluid pipe insection; and

Fig. 5 is an elevational view static element.

Fig. 1 illustrates typical app a section indicated by line 3--3 ofshow-' of the thermoaratus to which my control system may be applied,such as a refrigerating system employing a heavy propellant ofcomparatively high boiling point, for example mercury, and a fri'gerantsuch as water: same general character as identified patent-of Eastman A.

This .system may be provided with a 2 into one suitable flue 4 may behaving a central firebox a burner 3 projects. A

lighter, .more volatile re this system bein of the disclosed in theabove- Weaver. a

boiler 1 end 'of which rigerating provided to permit exhaustion of gasesfrom the duct 6 firebox, and a fuel supply may lie-connected to theburner 3, being arranged-to receive fuel from "any suitable source suchmains.

as the city gas A vapor duct '7 extends upwardly from the boiler 1 to anaspirator nozzle into an entraining chamber 9.

8 whichmroiects A vapor duct 10 connects chamber 9' with the upper partof a cooler 12 which contains a liquid body of refrigerant such aswater. Propellent vapor passing from the nozzle 8 at high speed iseffective in entraining vapor from the cooler 12 and in causing rapidevaporation at the surface of the contained liquid thereby causing thecooler to have a low temperature. The mixture of propellant andrefrigerant vapors passes into the compression and condensing funnel 15which is aligned with the asplrator nozzle and which is provided withsuitable cooling means such' as fins 16, so that the high boiling pointpropellant may be condensed out of the vapor mixture. The funnel 15 isinclined and propellant condensed therein flows downwardly to adownwardly extending propellant drain 17.

An upwardly extending vapor duct 19 is joined to the intermediate partof a separating chamber 20, the upper portion of which is connected to arefrigerant condenser 21. The vapor received by the condenser 21' isliquefied and flows back to the chamber 20, passing out of the lowerpart of the same into the duct 22 which forms one leg of a trap 23 thatmay contain mercury. The opposite leg of this trap is connected by aduct 25 with the cooler 12. The condensed'refrigerant forms a liquidcolumn in duct 22, which reaches a suflicient height to balance themercury column in the opposite leg of the trap 23, so that therefrigerant from the bottom of the column passes through the trap intoduct 25 and thus returns to the cooler 12.

Preferably a system of this character may operate at subatmosphericpressure, and may be provided with means to interrupt the return ofpropellant to the boiler when the internal pressure of the system risesunduly, as for example, due to leakage of atmospheric air into thesystem. The system preferably may be provided with a purger orevacuating means automatically operable to exhaust gases fromthe systemto aid in maintaining a low internal pressure and to compensate-for anyslight leakage that may occur. For this purpose a duct 30 is connectedto the. upper part of the condenser 21 and is arranged to receivenon-condensable gases. The propellant from the drain 1'? flows through atrap 31 that is connected to an entraining chamber 33, the upper part ofwhich communicates with the duct 30. A downwardly extending tube 34 ofrestricted diameter is connected to the lower part of chamber 32 and isso dimensioned that globules of the propellant will pass downwardlythrough the same, acting as separate liquid pistons between which bodiesof non-condensable gas may be entrained. The lower end of tube 34isconne'cted to a receptacle or standpipe 35 having an enlarged upperportion or reservoir 36 which is open to the air. A propellant receivingduct 39 is connected to the lower part of the standpipe and extendsupwardly to the downwardly inclined duct 40,.the juncture of ducts 39and 40 providing a spill-over which determines the pressure at the lowerend of the tube 34 and the standpipe 35. The duct 40 is joined to a mainpropellant return pipe 32, the lower end of which is connected to thelower part of boiler 1. The return pipe 32 is provided with an upwardlyextending continuation 29 that forms a drain to receive propellantparticles which may condense in the mixing chamber 9.

A mercury containing trap 27 may be connected to the bottom of thecooler 12 to receive stray propellant particles therefrom, this trapdensed out of the mixture in the funnel or con-- denser section 15 andthe refrigerant vapor passing upwardly to the refrigerant condenser 21;the condensed refrigerant from the latter passes through the pressurebalancing trap 23. and thus returns to the cooler 12.

The major portion of the condensed propellant is received by the drain17 and thus passes through trap 31 to the chamber 32 and the tube 34.Non-condensable gases which occur in the system are received from thepipe 30 and entrained between propellant globules that pass downwardlythrough tube 34. The standpipe 35 normally contains a column of mercurywhich has its upper surface exposed to atmospheric pressure;accordingly, the non-condensable gases =bubble upwardly through thismercury column and are exhausted to the atmosphere. The merity,refrigerant vapor may be entrained in the pipe 34 and rise to' the topof the mercury column in standpipe 35, thus being emitted from thesystem. However, the amount of vapor which is thus exhausted even over along period of time is substantially negligible. Should the pressurewithin the system rise due to'the leakage of gases or atmospheric airinto the system at a greater rate than it may be exhausted by thepurger, the internal pressure will cause the mercury level in standpipe.35 to rise against atmospheric pressure so that the mercury may flowupwardly into the reservoir 36. The capacity of this part of the systemis so determined that an increase in the internal pressure of the systemto' a predetermined point will result in the collection of so muchmercury in the standpipe and the reservoir that continued flow ofmercury upwardly through duct 39 to duct 40 will be interrupted and thesupply of propellant in the boiler will quickly become depleted so thatvapor may pass upwardly.

into duct 32.

It will be understood that a system of the character just disclosed hasbeen described as representing a typical arrangement to which my safetycontrol means is particularly applicable, but that this control meansmay be applied to many other types of systems, for example, to a systemsuch as shown in my copending application Serial No. 503,006 which isprovided with a propellant lifter to permit the top of the pressurebalancing column of mercury which re'--- turns propellant to the boilerto be at a level above the propellant condenser.

In accordance with the present invention, control means may beassociated with a duct which contains-liquid and is connected to thevaporizer below the normal liquid level therein, the control theconnection 51 ment with the casing and to tion 59 o! the valve membermay be means'being arranged to be responsive to an elevation in thetemperature of the fluid within the duct, so that whenever the fluid isdisplaced of heat to the boiler in whatever manner that supply may beeffected; thus with a boiler having a burner for a combustible mixture,such as a 'mixture of illuminating gas and air, the control means mayinclude a valve to interrupt the flow of at least one of the ingredientsof combustion to the burner. This control means includes a part tointerrupt-the flow of fuel or energy to the heating iactor 3 of theboiler and accordingly may be associated with the fuel supply duct 6. Asshown in Fig. 2, the latter may be connected to a casing 50 which isdisposed in heat transfer relation to the duct 32, and preferably islocated adjoining flue .4. Figs. 2, 3 and 4 illustrate this arrangementin greater detail, it being evident that the casing 50 is provided withan outlet portion or connection 51 which is ioinedto the section of duct6 that extends to the burner and also is provided with the inletconnection 52 that is connected to the section of duct 6 that isconnected to the gas mains or other source or fuel supply.

The casing 50 is provided with a substantially cylindrical recess whichhas an open end opposite and which is provided with internal threads 54to receive external threads upon acylindrical member 55. The latter maybe provided with an external head 56 to facilitate its movement into andout of threaded engageprovide a shoulder for engagement with an annularface of the casing. V

Member 56 is provided with a cylinder internal recess 5'7 which receivesa slidable valve member 58, the latter having a substantiallycylindrical body portion 59 with a centralrecess 60 that receives acompression spring 61. The latter has one end normally in engagementwith valve 58 and its opposite end in engagement with the head 56 ofmember 55 so that it tends to urge the valve toward the connection 51.

The mouth of a passage which extends to onnection 51 is provided with abeveled surface 66 1.0 iorm'a valve seat that cooperates with a taperedextension 69 upon the end of member 58. Thus when the spring 61 is freeto operate, the member 69 engages the valve seat 66 and flow or fuelfrom the inlet 52 through the casing 50 to the outlet 51 is prevented.

During normal operationof the system, however, I prefer to provide meanslocking the valve in open position. Such means comprises a segmentalmember '70 of thermostatic metal which is illustrated more particularlyin Figs. 3 and 5,

this thermostatic member having an end portion secured by a fasteningelement '71 in a groove '72 in the cylindrical member 55. The bodyporcut away to clear the end of element '71 (Fig. 3) A continuation ofthe groove '72 provides a slot '73 which permits the thermostatic memberto engage a segmental groove 74 in valve 58, thereby locking the latterin its open pos'tion and holding the spring 61 under compression. Themember'70 is arranged,-,however, so that in response to a suitableincrease in its temperature, it will spring out of engagement with thegroove '74, thus releasing the valve member 58, so that the spring isefiective in engaging valve surface 69 with the seat 66, therebyinterrupting the fuel flow.

A plate having a semi-cylindrical recess is secured by screws 82 to aportion ofthe casing. 50 which has a complementarily formed recess, 80these recesses cooperating to provide a substantially cylindricalopening through which the duct 32 extends, the plate and screws beingefiective in clamping the duct in good heat transfer relation to casing50. 85 7 During normal operation of the system the duct portion 32adjoining casing50 contains liq- Y uid propellant and the valve will beheld in its open position. When -the liquid in the boiler 1 is depletedfor any reason, as, for example, due

to the clogging of the aspirator nozzle 8, the vapor will displace theliquid 'mercury in the lower part of the duct 32 and vapor will pass tothe region of the casing 50. Obviously this propellant vapor hasatemperature which is distinctly higher than that of the liquid normallycontained in the duct 32, and can rapidly conduct heat to the casing 50so that the thermo-'- static element '70 expands gagement with thegroove ber 58, permitting the and moves out of en- 74 in the valvememlatter to be moved'to its closedposition by spring 61. It is evidentthat in case of an 'undue increase in the internal pressure of thesystem, for example due to rapid leakage of atmospheric air into thesystem, the mercury will rise into the reservoir 36 and will no longerbe supplied to the duct 32 through the duct 40. The downwardly flowingpropellant received by duct 32 from duct 40 normally aids the cooling ofthe pipe 32 and casing 50, thus tending to offset the heating eilect oithe juxtaposed 'flue, but as soon as this flow is interrupted, for

example, due to the collection of propellant in receptacle 36 the heatfrom the flue is efiective in causing a rapid increase in thetemperatureof the casing 50 and the heat-responsive element '70. Thusthe heat from iiue 4 not only causes the more rapid operation of theshut-ofi device, in response to abnormal operating conditions; but undercertain conditions, this heat may be eflective in causing operation ofthe device, be-' fore the liquid propellant passes out of the lower endor duct 32. c Accordingly further supply of fuel to the boiler isprevented and theoperation of the system is interrupted. In order topermi the system to resume operation, it is necessary to remove-themembers 55 and 58 from the casing 50, reassembling them in their normalposition with the spring 61 compressed so that the cooled and contractedthermostatic element 70 may again engage the groove '74. Thisarrangement is efiective in calling attention to the condition which hascaused the development of the high pressure in the vaporizer and anindication is thus afiorded of the ad'visability of expert attention tothe system.

From the foregoing, it will be evident that I have provided safetycontrol means to interrupt the supply of heat to the boiler which isconnected to a duct that normally contains liquid, but which willcontain vapor whenever the boiler pressure becomes inordinately high orwhenever the liquid level becomes undesirably low in the boiler.Accordingly, this arrangement is efiective in interrupting the operationof the system when the flow of propellant to the boiler isinterrupted-or undulyimpeded as for example due to the leakage ofatmospheric air into the system and the collection of mercury inreservoir 36. Furthera more, should the aspirator nozzle 8 become 15clogged the pressure in the boiler will become sufficiently high todisplace the mercury and to cause vapor to flow upwardly into the duct32 thus causing operation of the shut-off means. If a leak shoulddevelop in the boiler so that the level of the mercury should becomeunduly low, a similar result will take place. An arrangement of thischaracter is particularly advantageous with a system having a propellantlifter such as that disclosed in my copending application, Serial No.503,006 which is included by reference herein. Should such a propellentlifter fail to operate for any reason and thus terminate the return ofpropellant to the boiler, the shut-off means will operate in the samemanner to protect the system against injury and to prevent burning ofthe boiler. It is thus evident that I have provided means to interruptoperation of the system under practically any condition which would makecontinued operation dangerous or undesirable.

It should be understood that the present disclosure is for the purposeof illustration only and that this invention includes all modificationsand equivalents which fall within the scope of the appended claims.

I claim:

1. Apparatus of the class described comprising a boiler, a burnerassociated therewith, a passage supplying fluid to the burner, a vaporoutlet pipe connected to the boiler, a duct normally containing liquidconnected to the boiler, a heat distortable thermostat in heat transferrelation to a portion of the duct remote from the boiler, said ductbeing arranged so that depletion of liquid in the boiler will cause hotvapor to pass into the duct and effect movement of the thermostat, ashut-off valve in the fluid passage, a spring urging the valve towardits closed position, the thermostat normally locking the valve in openposition and when actuated by heat releasing the valve so that it isclosed by the spring, thus interrupting the flow of fluid to the burner.

2. Apparatus of the class described, comprising a boiler, a burnerassociated therewith, a fuel supply pipe leading to the boiler, a liquidsupply duct connected to the boiler and normally containing a column ofliquid to balance boiler pressure and to supply liquid to the boiler, avalve casing in heat transfer relation to a portion of said duct andconnected to the pipe, a movable valve member in said casing arrangedwhen in engagement with a seat in the casing to interrupt fuel flowthrough the pipe, a spring in the casing urging the valve toward theseat, a thermostat normally engaging a' recess in the valve member tohold it away from the seat, said thermostat being movable out of saidrecess to release the valve in response to a high temperature.

3. Apparatus of the class described comprising a boiler, a vapor outletpipe connected to the upper part of the boiler, an aspirator .nozzleconnected to said pipe, a duct connected to the lower part of the boilerand normally containing a-displaceable liquid column, said duct havingan upper portion disposed above the boiler and normally free fromliquid, means for supplying heat to the boiler, a shut-oil to terminatethe supply of heat to the boiler, a thermostat 0 rable under theinfluence of heat to cause the s ut-ofi to interrupt the supply ofheat,,said

thermostat being disposed adjoining the duct, whereby clogging of thenozzle and consequent high vapor pressure in the boiler causes vaporfrom the boiler to displace the liquid column in the duct, so that thethermostat will causethe shut-off to operate.

4. Apparatus of the class described comprising a fluid circuit includinga boiler, a vapor outlet pipe connected to the upper part of the boiler,a supply duct connected to the lower part of the boiler and normallycontaining a displaceable liquid column, means for supplying heat to theboiler, a shut-off to terminate the supply of heat, a heat-responsiveelement operable'under the influence of heat to cause the shut-off. tointerrupt the supply of heat, said heat-responsive element beingdisposed adjoining the supply duct, and means operable in response to apressure change in the circuit to interrupt flow of liquid into thesupply duct and thence to the boiler, whereby vapor will flow to theregion of the thermostat and cause operation of the shut-off.

5. Apparatus of the class described comprising a fluid circuit having alow pressure portion normally operating at subatmospheric pressure andincluding a boiler, a vapor outlet pipe connected to the upper part ofthe boiler, a supply duct connected to the lower part of the boiler andnormally containing a displaceable liquid column, means for supplyingheat to the boiler, a shutolf to terminate the supply of heat, athermostat .operable under the influence of heat to cause the shut-offto interrupt the supply of heat, said thermostat being disposedadjoining the supply duct, and means operable in response to an increasein the pressure of said low pressure portion of the circuit to interruptflow of liquid into the supply duct and thence to the boiler, wherebyvapor will flow to the region of the thermostat and cause operation ofthe shutoflf.

6. Apparatus of the class described comprising a fluid circuit having alow pressure portion normally operating at subatmospheric pressure andincluding 'a boiler, a vapor outlet pipe connected to the upper part ofthe boiler, a supply duct connected to the lower part of the boiler andnormally containing a displaceable liquid column, means for supplyingheat to the boiler,

a shut-off to terminate the supply of heat, a thermostat operable underthe influence of heat to cause the shut-off to interrupt the supply ofheat, said thermostat being disposed adjoining t supply duct, a ductconnected to said circ and normally containing a liquid column with itsupper surface subject to atmospheric pressure, whereby increase of theinternal pressure will cause the height of said column to increase, thusdepleting the remainder of the system of liquid sufliciently tointerrupt the return of liquid to the boiler, whereby vapor will flow tothe region of the thermostat and cause operation ,of the shut-off.

7. Apparatus of the class described comprising a fluid circuit includinga boiler, a heater associated therewith, a supply duct connected to theboiler, a vapor duct connected to the boiler, and

a receptacle associated with the supply duct and communicating with theatmosphere, said receptacle containing a liquid column with its uppersurface exposed to atmospheric pressure and arranged so that the heightof said column may vary in response to the ratio between internalpressure of the system and atmospheric pressure, the receptacle having asuflicient capacity toprevent furtherflow of liquid through the supplyduct to the boiler when the pressure ratio reaches apredetermined'point, and control means operable to interrupt operationof the heater when the flow of liquid to the boiler is thus interruped.

8. Apparatus of the class described comprising a fluid circuit includinga boiler, a heater associated therewith, a supply duct connected to theboiler, a vapor duct connected to the boiler, and

- a receptacle associated with the supply duct and a predeterminedportion of the receptacle tostop operation of the heater.

9. Apparatus of the class described comprising a fluid circuit having alow pressure portion normally operating at subatmospheric pressure,means for causing fluid circulation in said circuit, and meansassociated with said first means to interrupt the circulation of fluidin response to an undue rise in the pressure of said low pressureportion of the circuit.

10. Apparatus of the class described comprising a fluid circuit having alow pressure portion normally operating at subatmospheric pressure,

means for causing fluid circulation in said circuit,

purging means operable to exhaust non-condensable gases from the system,and means associated with said first means and the purging means tointerrupt the circulation of fluid in response to an undue rise in thepressure of said low pressure portion of the circuit.

11. Apparatus of the class described, comprising a boiler, a combustionchamber associated therewith, a flue connected to said chamber, a vaporoutlet duct connected to the upper part of the boiler, a liquid supplyduct connected to the boiler below said outlet duct, a fuel linesupplying a combustible fluid to the combustion chamber, shut-01f meansassociated with said line and operable to impede the flow of fuel, aheat-responsive. element normally restraining the shut-off device fromoperating, said element being in heat transfer relation to said flue andliquid supply duct, heat from the flue being efl'ective in causing theheat-responsive element to release the shutoiT means, thus impeding fuelflow, when the flow of liquid through the supply duct is interrupted.

LYMAN F. WHITNEY.

